Transmitters are used in a variety of applications in which wireless operation is desired. For example, many movable barrier operators such as garage door openers, gate operators, and rolling shutter systems utilize transmitters to operate the movable barrier associated with the operator (i.e., to operate the door, gate, or shutter). Many of the transmitters supplied with these products are designed as single function, single frequency devices with a preset carrier frequency and use either a switch-selectable code or preset factory codes. A switch-selectable code is selected by the user setting a plurality of switches on the transmitter and a receiver of the movable barrier operator. Because both the transmitter and the receiver have matching switch-selected codes, the receiver can authenticate a signal sent from the transmitter that represents the switch-selected code.
Preset factory codes are programmed into the transmitter by its manufacturer and are learned by a receiver of a movable barrier operator by the user causing a controller (e.g., microcontroller or other processor such as a microprocessor, gate array or the like) of the receiver to enter a learn mode. After the receiver enters the learn mode, the user activates the transmitter so that the transmitter transmits a signal representing the factory programmed code stored in the transmitter. The receiver of the movable barrier operator receives the signal and determines the preset factory code from the signal. The movable barrier operator thereby “learns” the code of the transmitter. After the receiver exits the learn mode, the operator will operate in response to receiving a signal from the transmitter that represents the factory programmed code.
Rolling code transmitters may be used with movable barrier operator to provide additional security. An example of a rolling code generating transmitter of the type described herein is disclosed in U.S. Pat. No. 6,154,544 issued Nov. 28, 2000, which is hereby incorporated herein by reference.
Some prior portable transmitters are not rechargeable so they must have one or more large batteries that can last for multiple years. The one or more batteries are a driving design factor that requires the entire transmitter to be larger. Alternatively, some transmitters are integrated into vehicles so that they are powered by the vehicle and do not need a battery. These integrated transmitters are not suitable for many applications, because they cannot be removed to be used by pedestrians or transferred between vehicles.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions and/or relative positioning of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various embodiments of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments. It will further be appreciated that certain actions and/or steps may be described or depicted in a particular order of occurrence while those skilled in the art will understand that such specificity with respect to sequence is not actually required. It will also be understood that the terms and expressions used herein have the ordinary technical meaning as is accorded to such terms and expressions by persons skilled in the technical field as set forth above except where different specific meanings have otherwise been set forth herein.